fix(continuum): honor @continuum-restore option for auto-restore on server start

[MattKotsenas]

Summary

set -g @continuum-restore 'on' is documented in psmux-continuum/README.md as "auto-restore on psmux server start", but the option is silently ignored. Auto-save works; auto-restore never fires. After a server restart users get a fresh empty session, and ~15 min later the auto-save loop overwrites the last pointer with that empty state, pruning the recovery target.

This bit me after an unexpected reboot; saved session was on disk, last had been clobbered to point at an empty save, and nothing fired on startup.

Root cause

Two entry points with what appears to be disjoint feature sets:

Option	psmux-continuum.ps1	plugin.conf
@continuum-restore	honored (lines 163–168)	line 19 commented out
@continuum-save-interval	honored	hardcoded 15
@continuum-boot	honored	not handled

ppm.ps1 (lines 391–398) deliberately skips .ps1 entry points when plugin.conf exists, so the only code that reads @continuum-* options never runs. Only plugin.conf is sourced and it has the restore hook commented out.

Empirical evidence on a real install:

$ psmux show-options -g | findstr @continuum
@continuum-restore "on"

$ psmux show-hooks -g
client-attached -> run-shell "...auto_save.ps1 ..."
# (no restore hook registered)

Second bug found while fixing this

The commented-out line uses after-new-session. Live hook-probe on a fresh psmux server:

after-new-session  => no
session-created    => FIRED
client-attached    => FIRED

after-new-session does not fire on the first session creation in a fresh server, only on subsequent ones. So simply uncommenting that line would still have left auto-restore broken after one scenario where it really matters (server restart). This PR uses session-created instead.

Fix

• plugin.conf: unconditionally register the session-created hook -> auto_restore.ps1.
• auto_restore.ps1: read @continuum-restore at exec time, exit early if not on. Keeps plugin.conf free of nested if-shell quoting and evaluates the option at hook-fire time (robust to option-set ordering vs. config sourcing).
• Add a @continuum-restore-fired one-shot marker. Without this guard the hook re-enters for every psmux new-session call that restore.ps1 itself makes.
• Heredoc in psmux-continuum.ps1 kept byte-identical to scripts/auto_restore.ps1 to preserve the existing regeneration invariant.

Validation

• ✅ session-created fires on first session - live-probed.
• ✅ after-new-session does not fire on first session - live-probed.
• ✅ Hook registers correctly via patched plugin.conf - verified with psmux show-hooks -g.
• ✅ Opt-out path: when @continuum-restore is unset or off, auto_restore.ps1 exits early without invoking restore.ps1 or setting the fired marker - live-tested.
• ✅ Both .ps1 files parse cleanly ([System.Management.Automation.Language.Parser]::ParseFile).
• ✅ Heredoc and scripts/auto_restore.ps1 are byte-identical (AST-extracted + string-compared).

Overlap with PR #13

PR #13 (singleton-guard auto-save) touches the same files. This PR's diff is orthogonal and trivially rebases either way.

[Copilot]

Pull request overview

Fixes auto-restore for psmux-continuum: the @continuum-restore option was documented but never honored because plugin.conf (the only entry point sourced when present) had the restore hook commented out. This PR registers the hook unconditionally and moves the opt-in check inside auto_restore.ps1, also switching from after-new-session (which doesn't fire for the very first session in a fresh server) to session-created.

Changes:

• plugin.conf: register session-created hook unconditionally to invoke auto_restore.ps1.
• auto_restore.ps1 (and the byte-identical heredoc in psmux-continuum.ps1): gate execution on @continuum-restore == 'on', and use a @continuum-restore-fired one-shot marker to prevent re-entry when restore.ps1 calls new-session for each saved session.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
psmux-continuum/plugin.conf	Replaces commented after-new-session hook with an active session-created hook delegating opt-in to the script.
psmux-continuum/scripts/auto_restore.ps1	Adds Get-PsmuxBin resolver, opt-in check on @continuum-restore, and one-shot guard via @continuum-restore-fired.
psmux-continuum/psmux-continuum.ps1	Updates the heredoc that generates auto_restore.ps1 to remain byte-identical with the standalone artifact.

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[tarikguney]

Thank you for the PR, @MattKotsenas. Much appreciated. Everything looks good to me. I’ll go ahead and merge it.