refactor: split pipeline_runner_browser into focused mixins

[tom-sapletta-com]

Summary

• Slim pipeline_runner_browser.py to single-action DOM entry (~114 lines)
• Extract legacy _run_dom_multi_action to pipeline_runner_browser_multi.py
• Extract ActionDispatcher path to pipeline_runner_browser_dispatch.py
• Compose PipelineRunner from the three browser mixins

Test plan

• CI passes (3.11, 3.12)
• from nlp2cmd.pipeline_runner import PipelineRunner works

Made with Cursor

[ifuri-validator-agent]

Deterministic Validator approval for exact head 5c6938d5169ed58b41c0b759fc13e18d5b40c7cd.

Ticket: ticket-000
Correlation ID: nlp2cmd-pr-3-ticket-000
Model: zai/glm-5.3
Advisory LLM review: LLM_UNAVAILABLE
Reason: advisory_review_budget_exceeded: full review requires 17 chunks; limit is 8
This approval rests on the deterministic checks alone; no advisory opinion was recorded for this head.
Merge will be attempted after this approval when explicitly authorized.

Decision record (recomputable)

DECISION D-000-1021
TICKET ticket-000
HEAD_SHA 5c6938d5169ed58b41c0b759fc13e18d5b40c7cd
CORRELATION_ID nlp2cmd-pr-3-ticket-000
ACTOR agent:ifuri-validator-agent[bot]
APPLIED_RULE P-CORE-015
INPUT author_login = "tom-sapletta-com"
INPUT observed_checks = ["test (3.11)=PASS","test (3.12)=PASS"]
INPUT required_checks = ["test (3.11)","test (3.12)"]
INPUT required_checks_source = "protected registry + GitHub applied rules (env/request)"
INPUT reviewer_login = "ifuri-validator-agent[bot]"
INPUT superseded_checks = []
VERDICT APPROVE AUTHORITY DETERMINISTIC
REJECTED REQUEST_CHANGES BECAUSE NO_UNSAFE_CHANGE_REASON_FOUND
ADVISORY llm_verdict = "" MODEL "zai/glm-5.3"
ASSERT VERDICT_AUTHORITY != "ADVISORY"