When an admin lands a vision pull, only the fenced vision block of the direction is rewritten, and the owner's own words are kept word for word #6230

When an admin lands a vision pull, the repository's direction now gains or refreshes a fenced block, and the owner's words outside it stay untouched. The new tests, vision-pull, merge-actors and the event-audience coverage tests pass, and tsc and the design lint are clean. I did not run the whole suite; the forge's check does that on push.

What changed

• Vision pulls: mergePull calls landVision (src/crew/vision.ts) after the merge. It acts only when the pull's placement marks it as a vision pull (isVisionPull in src/core/placements.ts). A branch named vision-… without that placement is ignored.
• Admin merge: if the merger canAdmin the repository, the block between <!-- forge:vision:start --> and <!-- forge:vision:end --> is regenerated from the landed VISION.md. It holds the purpose, the order-of-work names and the rules.

- It writes as the merger only, never as autonomyBy. - With no block yet, one is appended after the owner's text. - Everything outside the block is kept byte for byte. - The whole direction stays at or under 2,000 characters. Rules are dropped from the end first; if the owner's text leaves no room, nothing is written. - A repo.settings_updated event lists autonomyDirection when the direction changed.

• Orphan marker: a start marker without an end, a duplicated marker or a reversed pair leaves the direction unchanged and logs why.
• Non-admin merge: the direction is unchanged and no comment is posted. A repo.vision_kept event is written, classified as visible to readers. The pull page renders it in the conversation as the forge's own line ("the forge kept the repository's direction as it was: only an admin's merge rewrites it").
• Tests: test/vision-land.test.ts covers an admin merge with the owner's text before and after the block, a writer merge, an orphan start marker, a reversed marker pair, a vision- branch with no placement, the 2,000-character bound, and the forge's line on the pull page.

Not done

• There is no event or page line for an orphan marker; it is only logged, as the issue asked.
• The block is regenerated on every admin vision merge, not only when VISION.md changed.
• There is no settings-page control for the block.

To try it

1. Put a thought through triage so it opens a vision pull.
2. Merge that pull as a repository admin.
3. The direction in settings now ends with the fenced block.
4. Merge another vision pull as a writer who isn't an admin, and the pull page shows the forge's line.

Closes #5834

When an admin lands a vision pull, the repository's direction now gains or refreshes a fenced block, and the owner's words outside it stay untouched. The new tests, vision-pull, merge-actors and the event-audience coverage tests pass, and tsc and the design lint are clean. I did not run the whole suite; the forge's check does that on push.

What changed

• Vision pulls: mergePull calls landVision (src/crew/vision.ts) after the merge. It acts only when the pull's placement marks it as a vision pull (isVisionPull in src/core/placements.ts). A branch named vision-… without that placement is ignored.
• Admin merge: if the merger canAdmin the repository, the block between <!-- forge:vision:start --> and <!-- forge:vision:end --> is regenerated from the landed VISION.md. It holds the purpose, the order-of-work names and the rules.

- It writes as the merger only, never as autonomyBy. - With no block yet, one is appended after the owner's text. - Everything outside the block is kept byte for byte. - The whole direction stays at or under 2,000 characters. Rules are dropped from the end first; if the owner's text leaves no room, nothing is written. - A repo.settings_updated event lists autonomyDirection when the direction changed.

• Orphan marker: a start marker without an end, a duplicated marker or a reversed pair leaves the direction unchanged and logs why.
• Non-admin merge: the direction is unchanged and no comment is posted. A repo.vision_kept event is written, classified as visible to readers. The pull page renders it in the conversation as the forge's own line ("the forge kept the repository's direction as it was: only an admin's merge rewrites it").
• Tests: test/vision-land.test.ts covers an admin merge with the owner's text before and after the block, a writer merge, an orphan start marker, a reversed marker pair, a vision- branch with no placement, the 2,000-character bound, and the forge's line on the pull page.

Not done

• There is no event or page line for an orphan marker; it is only logged, as the issue asked.
• The block is regenerated on every admin vision merge, not only when VISION.md changed.
• There is no settings-page control for the block.

To try it

1. Put a thought through triage so it opens a vision pull.
2. Merge that pull as a repository admin.
3. The direction in settings now ends with the fenced block.
4. Merge another vision pull as a writer who isn't an admin, and the pull page shows the forge's line.