The backlog loop prompts through the run's own driver session, so a backlog
turn carries the same signal protocol as any other turn. promptItem only
parsed await gates, so everything else was dropped: showMarkdown() views never
reached the rail, setSessionName() was ignored, and setReadyForMerge() never
emitted ready-for-merge, which is what maybeFirePostMerge gates on. So
--post-merge could not fire from backlog work, now that the queue is where
post-merge writes its follow-ups (#558) and the knowledge docs (#537).

The cause was duplication: emitTurnSignals was byte-identical in run.ts and
prompt-run.ts, and the third turn site never got a copy. It is now one
createTurnSignalEmitter used by all three. The backlog loop keeps a single
emitter for the whole backlog, so ready-for-merge still fires once.

Closes #563

…597)

* refactor(framework): preset prompts use ${{ tf.params.what }}, retire <PARAM:name> (#594)

Rom's updated #326 OP and the preset OPs switched the preset blank from
<PARAM:what> to ${{ tf.params.what }}, the same fragment syntax the system
prompt uses. Move the presets onto renderTemplate and delete the bespoke
preset-params.ts primitive, which is then fully unused.

render<Name>Prompt(what) is unchanged: byte-identical output for all 5
presets, default and custom, proven with a before/after render probe.

Prereq for #326's post-merge preset filePath entries.

Closes #594

* feat(framework): post-merge entries carry the preset filePath (#596)

Rom's updated #326 OP block 2 changed the post-merge TODO entries from a
bare preset name the agent had to guess to a real file it opens:

  Apply .the-framework/presets/maintainability.md with tf.params.what set
  to "changes introduced by <session>"

- new presets.ts: PRESETS registry (keyed by file stem, matching Rom's
  tf.presets.security_audit key), presetFilePath, presetContext,
  materializePresets
- installProject materializes the 5 presets into .the-framework/presets/*.md
  so filePath resolves; gitignored, so they track the framework version
- post-merge ## Maintenance re-flattened to Rom's OP block 2; drift snapshot
  updated (turns the drift check green)
- tf.presets.<name>.filePath plumbed through PostMergeContext, defaulted
  from presetContext()

Closes the fidelity gap #558 introduced. Proven end to end: install
materializes the files, and the rendered entry's filePath points at one
that exists on disk.

Closes #596