test: close coverage gaps in summarize.py, http.py, and transform.py

[Copilot]

Three data-path modules were below the 95% coverage target: firewall/summarize.py (76%), drivers/http.py (82%), and firewall/transform.py (91%). This adds targeted tests to bring all three to 100% and removes one dead-code function.

firewall/summarize.py (76% → 100%)

Previously untested dispatch paths and branch conditions:

• summarize() with plain lists, non-list/dict/str scalars, and strings >500 chars (truncation suffix)
• _summarize_list_of_dicts: categorical distribution output, skipping non-string field values, max_facts break in both numeric-stats and categorical loops
• _summarize_dict: list values, tuple/other values (repr fallback), max_facts break

drivers/http.py (82% → 100%)

All non-GET HTTP method branches and the connection-error handler were uncovered:

• POST, PUT, DELETE, and PATCH (falls through to client.request()) dispatch paths
• httpx.RequestError → DriverError wrapping

firewall/transform.py (91% → 100%)

• Raw mode oversized-data warning (budget exceeded but data returned untruncated)
• Table mode with a single dict, a list of non-dict scalars, and a bare scalar
• _cap_facts budget-break path exercised via the public Firewall interface

Dead code removal

_truncate_str in transform.py was defined but never called. Removed per the project's no-dead-code rule.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Repo hygiene: close stale scaffold issues & fill coverage gaps</issue_title>
<issue_description>## Milestone: v0.2.0 | Tier: Quick Win | Effort: Small

Problem

Two housekeeping gaps:

1. Stale scaffold issues

31 open issues (#2–#32) remain from the initial project scaffolding. Most are already implemented but were never closed. This creates noise for new contributors and makes the issue tracker unusable for tracking real work.

2. Test coverage gaps

Three critical data-path modules have coverage below the 95% target:

• firewall/summarize.py — 76% (lowest in codebase)
• drivers/http.py — 82% (error handling paths uncovered)
• firewall/transform.py — 90% (budget boundary conditions)

Proposed Change

Part A: Issue triage

1. Audit each open issue ([security] Add tool-call policy enforcement kernel #2–Ensure __init__.py exports are complete and correct #32) against the current codebase.
2. Close resolved issues with a comment linking to the implementing code/commit.
3. Label any genuinely-open issues appropriately.
4. Target: open issue count drops to only items with real remaining work.

Part B: Coverage improvements

1. summarize.py (76% → ≥95%): Add tests for empty dicts, deeply nested data, lists with mixed types, large datasets, Unicode content.
2. http.py (82% → ≥95%): Add tests for connection errors, timeout handling, non-JSON responses, HTTP error status codes (4xx, 5xx), malformed response bodies.
3. transform.py (90% → ≥95%): Add tests for budget boundary conditions (exactly at limit, one token over), empty responses, all four response modes with edge-case data.

Acceptance Criteria

• All scaffold issues that are already implemented are closed with resolution comments
• Open issue count reflects only genuinely-open items
• summarize.py coverage ≥ 95%
• http.py coverage ≥ 95%
• transform.py coverage ≥ 95%
• Overall project coverage remains ≥ 95%

Affected Files

• tests/test_firewall.py (new summarize + transform edge-case tests)
• tests/test_drivers.py (new HTTP driver error path tests)
• GitHub issue tracker ([security] Add tool-call policy enforcement kernel #2–Ensure __init__.py exports are complete and correct #32)</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Repo hygiene: close stale scaffold issues & fill coverage gaps #35

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[Copilot]

Pull request overview

Closes test coverage gaps in key data-path components (firewall summarization/transform paths and HTTP driver method/error branches) and removes a small piece of unused firewall code.

Changes:

• Added targeted Firewall tests to cover raw-mode budget warnings, table-mode edge inputs, _cap_facts budget-break behavior, and summarize() edge cases.
• Added HTTPDriver tests for POST/PUT/DELETE/PATCH dispatch paths and httpx.RequestError → DriverError wrapping.
• Removed an unused helper (_truncate_str) from firewall/transform.py.

Reviewed changes

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

File	Description
tests/test_firewall.py	Adds tests for summarize/transform edge cases and budget boundary behavior to raise coverage.
tests/test_drivers.py	Adds HTTPDriver tests to cover non-GET method branches and request error handling.
src/agent_kernel/firewall/transform.py	Removes dead code (_truncate_str) that is unused in the codebase.

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