refactor: decompose daemon handlers by capability-owned concern

[thymikee]

Blocked by: #2131. Do not start implementation until replay has one accepted daemon seam and the child plan is rebased onto current main.

Outcome

Decompose the remaining src/daemon/handlers hotspot by capability-owned concerns, with one executable child issue and reviewable PR per concern. This is an umbrella, not authorization for one directory-reorganization PR.

Required concern children

• session lifecycle: open, close, inventory, binding
• test-suite hosting only if it remains outside replay after the replay extraction
• perf and observability
• interaction execution and deferred outcomes

Each child issue must name exact source files, commands, current writer owners, store/state reads, capability imports, destination module, route adapter, behavior tests, structural boundary plants, and prerequisite PRs.

Interface rules

• One external façade per concern, shared by routing and contract tests.
• Compare a capability aggregate with existing owner operations; do not preselect either.
• No anonymous Pick<SessionState>/Pick<SessionStore> or copied state record.
• Foreign writes continue through existing R7 owners.
• A new abstraction needs either two real production consumers/implementations or a deletion argument strong enough to justify one implementation. A test adapter is not a second production seam.
• Shrink SessionCommandInput only by fields exclusive to the migrated concern; fields needed by unmigrated concerns remain until their slice.

Size constraint

This program exists to delete handler plumbing and narrow authority. Each child PR must target net production shrinkage, report gross additions/deletions and move-adjusted LOC, and remove superseded modules/tests/baseline slack. New façade ceremony without compensating deletion is a stop condition.

Proof per child

• Behavior contract through the current route before moving implementation.
• Planted behavior violation plus both forbidden deep-import directions.
• Exact focused tests, pnpm check:layering, fallow audit, and pnpm check:affected --run.
• Before/after state-shape, store-authority, capability, and cross-concern edges are diagnostic evidence; no arbitrary numerical pass threshold.

Done criteria

• Every concern has an executable child issue and dependency chain.
• Minimal handlers perform routing only.
• Session writes remain with declared owners and broad read/capability surfaces shrink.
• No sibling concern deep-imports another concern's internals.
• The full program produces a net reduction in production LOC.

[thymikee]

Re-audited against exact origin/main f513b1d4ae after #2166.

Reconciliation

• The umbrella still holds, but the original four bullets were not executable at reviewable size.
• Replay and replay-test implementation now live under the accepted src/daemon/replay/ facade/internal boundary. There is no remaining standalone test-suite concern to extract, so no test-suite child was created.
• Current src/daemon/handlers production surface is 90 files / 14,639 LOC. The relevant current slices are: open 5 files / 1,357 LOC; close 4 / 793; inventory 1 / 508; perf-observability 4 / 1,243; interaction/find 33 / 4,520.
• R7 is governing the write side: 19 writer-owned fields / 22 owner-file claims. The migration target remains broad read/store/capability authority, not inventing new writers.
• The current authority overlay shows 70 live SessionStore edges and 116 SessionState-shape edges repo-wide; handler files account for 50 and 55 respectively. These are diagnostic counts, not pass thresholds.

Executable child chain

Lifecycle/session route, serial because the files overlap:

• refactor(daemon): establish session lifecycle facade and neutral admission seams #2173 — neutral session device/admission seams plus lifecycle inventory facade
• refactor(daemon): move open lifecycle behind the session lifecycle facade #2174 — open lifecycle, blocked by refactor(daemon): establish session lifecycle facade and neutral admission seams #2173
• refactor(daemon): move close lifecycle behind the session lifecycle facade #2175 — close lifecycle, blocked by refactor(daemon): move open lifecycle behind the session lifecycle facade #2174
• refactor(daemon): move session observability behind one capability facade #2176 — perf/observability facade, blocked by refactor(daemon): move close lifecycle behind the session lifecycle facade #2175 (or explicitly stacked on its exact head)

Interaction route, independent of the lifecycle files:

• refactor(daemon): establish the interaction application facade #2177 — interaction application boundary and shared authority narrowing
• refactor(daemon): move interaction and find routes behind the interaction facade #2178 — interaction/find leaf routes, blocked by refactor(daemon): establish the interaction application facade #2177

#2173 and #2177 are the only safe parallel first wave. Each child names exact production files, commands, current reads/writers, capability inputs, destination/facade, route adapter, behavior coverage, planted structural violations, prerequisites, and a move-adjusted non-growth/shrink stop condition.

Replay adapters remain behind #2166's accepted daemon replay facade; this program must not reopen engine/package ownership or move executable snapshot policy.