relayburn-sdk: collapse parse_claude_session onto run_incremental (#346)

[willwashburn]

Summary

Last remaining cleanup from #346. PR #371 already landed items 2–6 plus
the codex/opencode half of item 1, but explicitly deferred the claude
side because the two parsers disagreed on trailing in-progress turns:

• ParseState (non-incremental) emits assistants without a
  stop_reason.
• run_incremental skips them and backs end_offset up so the next
  resume call re-reads them.

This PR collapses the two by threading an emit_in_progress: bool flag
through run_incremental:

• false → existing incremental semantics (skip + back up end_offset).
• true → use cursor_offset for end_offset and emit every working
  record, matching the prior ParseState::finish contract.

parse_claude_session_with_counter now builds a
ParseIncrementalOptions { start_offset: Some(0), .. }, calls
run_incremental(.., true), and converts via a new
From<ParseIncrementalResult> for ParseResult. The 333-line
ParseState struct + impl, the non-incremental record_root and
collect_explicit_claude_relationships helpers, and
derive_file_session_id are deleted. Net -374 LoC in
reader/claude.rs.

Test plan

• cargo build -p relayburn-sdk clean
• cargo test --workspace (all 781 tests pass, including the 53
  claude reader tests covering full-parse output, incremental
  output, and the resume cursor)
• cargo fmt --check on crates/relayburn-sdk/src/reader/claude.rs
  clean

Closes #346.

https://claude.ai/code/session_01FvHFirtBvP9m4jWjVcB6v7

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ℹ️ Recent review info

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Run ID: dd777b47-3452-4924-958d-ca890e6ebac7

📥 Commits

Reviewing files that changed from the base of the PR and between ad3ea7b and c1409cd.

📒 Files selected for processing (2)

• CHANGELOG.md
• crates/relayburn-sdk/src/reader/claude.rs

✅ Files skipped from review due to trivial changes (1)

• CHANGELOG.md

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📝 Walkthrough

Walkthrough

This PR consolidates duplicate parsing logic by refactoring parse_claude_session_with_counter to delegate to the incremental parser run_incremental with emit_in_progress=true, eliminating a redundant ParseState codepath. A From<ParseIncrementalResult> for ParseResult conversion wires the result types. Claude system tool/status field-key matching is expanded for robustness. Minor refactors preserve behavior throughout.

Changes

Parse Session Unification

Layer / File(s)	Summary
Type Conversion crates/relayburn-sdk/src/reader/claude.rs	Adds From<ParseIncrementalResult> for ParseResult trait implementation wiring turns, content, events, relationships, tool_result_events, user_turns, and evidence fields.
Sync Path Delegation crates/relayburn-sdk/src/reader/claude.rs	parse_claude_session_with_counter now builds ParseIncrementalOptions (start_offset=0, last_user_text=None) and delegates to run_incremental(..., emit_in_progress=true), then converts result via From trait.
Incremental Parser Signature and Behavior crates/relayburn-sdk/src/reader/claude.rs	run_incremental accepts new emit_in_progress parameter. When true, trailing partial JSON lines are processed so end_offset keeps cursor_offset and emits all seen content; when false, it backs up to the earliest incomplete boundary and skips emitting working records without stop_reason. Incremental entrypoint updated to call run_incremental(..., emit_in_progress=false).
Parser Field-Key Expansion crates/relayburn-sdk/src/reader/claude.rs	build_claude_system_tool_result_event expands tool_use_id key set; claude_system_event_status expands status-field key variants (status, state, result, terminal variants) for normalized lookup.
Minor Refactors and Formatting crates/relayburn-sdk/src/reader/claude.rs	UTF-8 trimming in prescan_nodes, relationship continuation/evidence accessor refactors, resume-marker token extraction, collect_errored_tool_use_ids formatting, and other call-formatting/line-break cleanups—logic preserved.
Tests / Regression crates/relayburn-sdk/src/reader/claude.rs	Adds unit test asserting parse_claude_session emits final turn when JSONL ends with a complete JSON object lacking a trailing \n.
Changelog Documentation CHANGELOG.md	Documents parse_claude_session delegation to incremental parser at offset 0, noting removal of duplicate ParseState codepath while keeping observable behavior unchanged.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• AgentWorkforce/burn#293: Both PRs modify the Claude parser implementation and parsing entrypoints (parse_claude_session / parse_claude_session_incremental and related types).
• AgentWorkforce/burn#372: Related changes to run_incremental/prescan and JSONL trailing/partial-line handling that overlap with this PR's stream behavior adjustments.
• AgentWorkforce/burn#352: Related refactor that consolidates alias-aware string_field helpers and influences Claude parsing/accessor handling.

Poem

🐰 I hopped through bytes and trimmed the fray,
One parser now leads the parsing play.
Incremental whispers, sync nods along,
JSON lines sing the same old song.
Cleaner paths — a carrot-fueled refactored day.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: collapsing parse_claude_session onto run_incremental, which is the primary objective of the PR.
Description check	✅ Passed	The description is comprehensive and directly related to the changeset, explaining the motivation, implementation approach, and testing performed.
Linked Issues check	✅ Passed	The PR addresses objective 1 from #346 by collapsing non-incremental parse_claude_session to delegate to run_incremental; other objectives (2-6) remain unaddressed in this PR.
Out of Scope Changes check	✅ Passed	All code changes relate to objective 1 from #346 (collapsing the claude parser). Minor refactors like UTF-8 trimming, accessor reformatting, and test updates are within scope.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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[devin-ai-integration]

Devin Review found 1 potential issue.

⚠️ 1 issue in files not directly in the diff

⚠️ Single-shot parse silently drops final line if file lacks trailing newline (crates/relayburn-sdk/src/reader/claude.rs:2171-2173)

The old ParseState codepath used BufReader::read_line, which returns the final line at EOF even without a trailing \n. The new delegation to run_incremental uses read_until(b'\n') with an explicit guard at crates/relayburn-sdk/src/reader/claude.rs:2171 that breaks when line_buf.last() != Some(&b'\n'). For the incremental path (emit_in_progress = false) this is correct — the next call re-reads from cursor_offset. But for the full single-shot parse (emit_in_progress = true), there is no subsequent call, so a syntactically complete JSON line that happens to lack a trailing newline (e.g. file truncated mid-write, or writer hadn't flushed the \n yet) is permanently and silently lost. The CHANGELOG states "Behavior is unchanged" but this is a semantic difference from the prior implementation.

View 3 additional findings in Devin Review.