fix(tangent): make an agent's pipeline rename stick everywhere the name shows

[camielvs]

Problem

An agent asked to name a pipeline calls set_pipeline_name. That renamed the
spec held in memory and nothing else, so it reported success while the file
stayed Draft and both resource lists kept showing the name recorded when the
pipeline was added.

Behind that sat a second problem: nothing asked for the rename in the first
place on the path that matters. The naming brief only covered pipelines an
agent creates — but a project opened from a prompt already holds one, named
after the request, so the agent "found the open canvas" and no rule applied.
And the brief is seeded into the session's memory, which is Prime's, while the
only agent holding set_pipeline_name is the remote editor, whose prompt said
nothing about naming at all.

Then a third: even once a rename did fire, the lists kept the old name for a
minute. Browser storage fires no event a rename in this tab would reach, and the
query behind those lists is keyed on the pointer, which a rename does not change.
The new name appeared on reload, which read as the rename silently failing.

What changed

The spec name is canonical and everything follows it. The rename goes
through the file first, and the name the file actually took is what the spec is
called. An agent picks a name without knowing what else this browser holds, so a
collision adjusts rather than overwriting — the rule create_pipeline already
follows — and the tool says so instead of letting the agent believe it got the
name it asked for:

Renamed to "Churn model 2" — "Churn model" was already taken.

Agent renames go through a new renamePipelineFileFor rather than the hook the
menu bar uses: that one also navigates, which is meaningless for a pipeline open
in a workarea tab rather than at a url of its own. The rename invalidates the
local-pipeline queries and retitles the open tab, which otherwise keeps
announcing the name it resolved when it opened.

Naming happens on the first turn, not at the end of the build. A pipeline
created from the opening prompt is marked as carrying a name nobody chose;
get_pipeline_state reports that as nameIsProvisional. Prime gets a
name_pipeline tool it calls alongside name_session and rename_project —
the opening message is enough to title a pipeline, so there is nothing to wait
for. It refuses a pipeline someone named deliberately, and drives the open tab's
bridge rather than the resource row, because only the bridge moves the spec, the
file and the row together. The editor keeps a fallback rule for a pipeline still
unnamed once its changes are in.

The mark lives on the spec rather than on the project resource because the agent
that acts on it reads the canvas and never sees the row.

Both resource lists ask what a pipeline is called now instead of trusting the
copy on the row, which also fixes the same staleness after a rename from the menu
bar. A name-only pointer is trusted only in the browser that wrote it — someone
else's "Churn model" is not the one this browser holds, and naming a row after it
would be naming the wrong pipeline. Unknown authorship is trusted, which is every
single-user backend.

useUnavailablePipelines becomes useLocalPipelineStatus in
services/projects: both pages need it now, and it answers two questions
(unreachable, and current name) rather than one.

Fixing the project page also meant separating two things that had shared one
prop: a row's display label and "this row opens a conversation elsewhere". A
renamed pipeline is still a row on this page, and overloading the label would
have made it open as a session and lose its Remove button.

Testing

• New renamePipelineFileFor.test.ts (6), useLocalPipelineStatus.test.ts (6),
  provisionalPipelineName.test.ts (4); createNamingHandlers.test.ts and
  serializeSpecForAi.test.ts extended.
• pnpm run validate clean; npx vitest run 321 files / 3256 tests green.
• Observed against a live agent on the previous revision: the rename fired and
  the collision message surfaced correctly, but the new name only reached the
  lists on reload — which is what the query invalidation here fixes. The
  first-turn name_pipeline path has not been exercised against a live agent
  yet.

🤖 Generated with Claude Code

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A preview build has been created at: 09-23-fix_make_an_agent_s_pipeline_rename_stick/97afd7e

[camielvs]

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This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
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• fix(tangent): make an agent's pipeline rename stick everywhere the name shows #2796 👈 (View in Graphite)
• fix(runs): say why the backend refused a run instead of that it did #2794 : 1 other dependent PR (#2798 )
• feat(tangent): brief the agent on naming, and on the project its runs belong to #2792
• feat(projects): fix cancelling, track shared projects, flag unreachable pipelines #2790
• feat(tangent): keep an agent's edits in frame on the canvas #2789
• feat(tangent): bring Tangent onto the dashboard #2787
• feat(tangent): show a project's runs on the tangent page #2786
• fix(projects): show an agent's run on the project it belongs to #2785
• fix(agent): submit a spec that came from the editor's store #2784
• chore: increase max turns in remote agent #2779
• fix(tangent): stop the tab strips scrolling up and down #2777
• feat(projects): make the agents' instructions a project document #2776
• feat(tangent): list the pipelines the backend holds #2775
• feat(projects): show a project's documents on both pages #2774
• fix(tangent): project window parity — share, new-session links, agent-created pipelines, and a folded-away project window #2773
• refactor(projects): describe a project's resources one way #2765
• feat(projects): delete and share a project from either page #2764
• feat: open a new project ready to work in #2763
• feat: let the project page and Tangent reach each other #2762
• fix: keep a long project name inside the tile it belongs to #2761
• feat: say so when Tangent cannot be reached #2760
• feat: open a project where the work happens #2759
• feat: run a pipeline inside a project #2754
• feat: add pipelines held in this browser to a project #2745
• feat: project page #2738
• feat: create a project from a tile in the grid #2735 : 2 other dependent PRs (#2736 , #2737 )
• feat: projects dashboard #2734
• chore: tangent - annotate runs submission to projectid #2758
• fix: tangent - proper debug sequence system prompt #2757
• fix: tangent - quick run button from mini content window #2744
• fix: tangent - remote agent send delta immediately #2743
• fix: tangent - mint proper authorization with tangent #2742
• feat: tangent - debug in tangent sequence #2741
• chore: add autolayout tool #2740
• feat: tangent - resource management via document entity #2733
• feat: tangent - interactive chips in tangent chat #2732
• chore: save id stack to replay ids on reloads #2731
• refactor: tangent - migrate tangetproectcontext onto mobx #2730
• feat: tangent - keep track of open tabs while switching sessions inside project #2729
• feat: tangent - remote agent for runview and editor #2728
• refactor: tangent - structured workarea target #2727
• feat: tangent - embedded pipeline run view #2726
• feat: tangent - embedded pipeline editor #2725
• feat: tangent - dynamic workarea remote tools #2724
• feat: tangent - resources management in project view #2723
• feat: tangent project view page #2722
• feat: workspaces and projects service #2720
• chore: api client for workspaces and projects #2719
• master

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[camielvs]

Folded into #2792 — the pipeline-rename plumbing is the other half of that PR's pipeline naming, so keeping them apart meant #2792 claimed to name pipelines while the rename only reached the spec in memory.