agent: harnessd IPC — the six-tool surface over line-delimited JSON

The agent's only door to the trust layer (SPEC 3.5, 10): harnessd
serves read_profile, read_ledger, read_playbook, read_target_source,
propose_patch, run_verdict over stdio JSON lines. propose_patch
enforces the path allowlist (relative paths only, no parent
components, no .git, target name validated) before git apply --check
+ apply rooted in the target workspace; run_verdict builds the
candidate into an isolated dir and hands off to the verdict pipeline
(pristine-rebuilt baseline included). Python client
(agent/hotpath_agent/harness.py) + tools.py rewired from stubs to
live calls.

E2E evidence: escape attempts refused (bad target name, ../ paths,
trust-layer diff touching config/accept.toml rejected before any
apply); benign doc patch applied, candidate built, full verdict ran
mechanically end to end -> +8.9% [1.079, 1.104] accepted (ship-tree
patches ride along as the candidate), ledger row phase1-ipc-smoke-001.

Phase 1 caveat recorded in the daemon header: same-uid filesystem
read-only enforcement still needs the separate-user/container setup.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2

results/pending/ff886433fec9.json.diff

@@ -0,0 +1,9 @@
+diff --git a/README.md b/README.md
+index 5ab2632..dadf761 100644
+--- a/README.md
++++ b/README.md
+@@ -586,3 +586,4 @@ See [the graph](https://github.com/XAMPPRocky/tokei/graphs/contributors) for a f
+ Tokei is distributed under the terms of both the MIT license and the Apache License (Version 2.0).
+ 
+ See [LICENCE-APACHE](./LICENCE-APACHE), [LICENCE-MIT](./LICENCE-MIT) for more information.
++<!-- hotpath ipc e2e marker -->