fix(hooks): register ToolFailureTracker + ISASync (shipped but never wired)

[krikauskis]

What

Registers two hooks that ship in the release but are never wired in settings.json:

• hooks/ToolFailureTracker.hook.ts on a new PostToolUseFailure event.
• hooks/ISASync.hook.ts as an async, self-filtering PostToolUse entry.

Why

Both hooks ship in v5.0.0, both declare their own trigger in their headers, and
hooks/README.md documents both as wired — but settings.json registers neither,
so neither hook ever fires. This is a documentation-vs-config drift.

ToolFailureTracker (grep -c ToolFailureTracker settings.json → 0): the hook
declares TRIGGER: PostToolUseFailure and hooks/README.md documents it under a
"PostToolUseFailure Hooks" section, but no PostToolUseFailure event exists in
settings.json. The observability hook meant to populate
MEMORY/OBSERVABILITY/tool-failures.jsonl never runs, so Pulse failure metrics are
silently empty for every user. (If a config instead wires this hook matcher-less
under PostToolUse, it fires on success too and logs a false tool_failure after
every call — registering it on the correct event fixes that failure mode as well.)

ISASync (grep -c ISASync settings.json → 0): ISASync is the documented sole
writer of session.phase/phaseHistory into work.json (see hooks/lib/isa-utils.ts
and the hook header), and hooks/README.md documents it as a PostToolUse hook — but it
is never wired. Result: no ISA → work.json sync ever fires, so the Pulse Algorithm phase
view (/api/algorithm) and the Agents pane are empty for every Algorithm run on a
stock install. The hook self-filters on MEMORY/WORK/**/ISA.md, so it is inert for all
other writes.

Change

Two additions to settings.json hooks, matching each hook's documented contract:

1. A PostToolUseFailure block registering ToolFailureTracker (async).
2. An async PostToolUse entry for ISASync (self-filtering; mirrors how
   ToolActivityTracker is already registered).

No hook-body change.

Testing

• Before: grep -c ToolFailureTracker settings.json → 0; grep -c ISASync settings.json → 0; no PostToolUseFailure key.
• After: both hooks registered; JSON validates. A failing tool call appends one structured event to MEMORY/OBSERVABILITY/tool-failures.jsonl (successful calls append nothing); an Algorithm task that writes MEMORY/WORK/<slug>/ISA.md syncs phase to work.json so /api/algorithm returns the live phase and the Agents pane populates.

Note for maintainers

The PostToolUseFailure registration assumes the Claude Code harness in your target
version emits a PostToolUseFailure hook event (the project documents it as one, and the
hook's own header declares it). If the harness has renamed/removed it, the alternative is
to keep ToolFailureTracker on PostToolUse and have it self-filter on a populated
failure field. PostToolUse (for ISASync) is unambiguously supported — five entries in
the same file already use it.