[story-skill-intercept] Intercept tool calls mid-session and forward to SessionLogger

[Blockchain-Oracle]

Source of truth: context/docs/stories/story-skill-intercept.md.
The body of this issue mirrors the story file. If they disagree, the story wins (see SOURCE_OF_TRUTH.md + REFERENCE_REPO_AUDIT.md).

Dependency issues: #1, #6

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Epic: Epic 4 — OpenClaw Skill
Estimated time: ~1.5h
Dependencies: story-log-schema, story-skill-init

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Narrative

As an OpenClaw integration developer, I need onToolCall to intercept every tool execution and append an ExecutionLogEntry to the SessionLogger, capturing inputs, outputs, and TEE metadata.

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Acceptance criteria

Given onToolCall(context, toolName, input, output) is implemented
And SessionManager has an active SessionLogger for the session
When a tool call (e.g., web_search, summarize) completes
Then onToolCall is invoked with the tool name and I/O
And SessionLogger.appendEntry() is called with:
  - seq: incrementing from 0
  - ts: current Unix timestamp ms
  - type: 'tool_call'
  - tool: toolName
  - inputHash: sha256(JSON.stringify(input))
  - outputHash: sha256(JSON.stringify(output))

Given 3 tool calls are executed in a session
When the session is inspected mid-run
Then SessionLogger has 3 entries in order

Given onToolCall encounters an error (e.g., invalid input)
When the error is caught
Then a log entry is still created (with error flag or type='tool_error')
And the error does not crash the session

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File modification map

Create:

• packages/openclaw-skill/src/hooks.ts — onToolCall implementation with input/output hashing
• packages/openclaw-skill/tests/skill.test.ts — Test 3 sequential tool calls, verify entries logged in order, error handling

Update:

• packages/openclaw-skill/src/index.ts — Wire onToolCall into skill exports
• packages/openclaw-skill/src/SessionManager.ts — Add getActiveLogger() method for hook access

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Shell verification

# Run skill tests:
pnpm --filter=openclaw-skill vitest run skill.test.ts
# Must exit 0 with >= 5 passing tests