bug(scip): index never converges — 'only N of M files indexed. Continuing.' on every run, and no summary is printed #1673

User report (scip-dotnet, mixed 46-file repo, LadybugDB):

• First cgc index . took ~11s and finished with no report at all — no file/function counts.
• Every subsequent cgc index . said "repository '.' has only 32 of 46 files indexed. Continuing.", re-ran, completed — and the next run said exactly the same thing. It never reaches "already indexed".

Root causes (verified in source)

1. Files can vanish from the SCIP path's accounting. The Tree-sitter supplement pass skips files whose parse returns an error or raises (continue with no node), and a failing add_file_to_graph for a SCIP-covered file likewise leaves nothing. The Tree-sitter pipeline gives every discovered file at least a minimal File node precisely so graph count == discovery census; the SCIP path only did this for the no-parser case. Result: the resume check (Repository-[:CONTAINS*]->File count vs estimate_processing_time census) can never converge, and 'Continuing' loops forever.
2. The SCIP path never populates last_index_summary, so cgc index finishes silently (and worse: a SCIP run in a process that previously ran the Tree-sitter pipeline would print the stale previous summary).
3. Census asymmetry: the resume check called estimate_processing_time without the context's cgcignore_path while the pipelines filter with it — a context-scoped ignore makes the expected count permanently higher than reality.
4. The 'only N of M' message names no files, so there is nothing actionable when the gap is real.

Fix

• Minimal-File-node fallbacks on every shortfall path in the SCIP pipeline (parse error, parse crash, write failure) — convergence by construction.
• SCIP pipeline populates the CLI summary (and the builder resets it before a SCIP run).
• estimate_processing_time accepts cgcignore_path and the resume check passes the context's.
• The 'Continuing' branch now lists up to 5 missing files by name.

Regression-tested with a fake scip module against a real embedded database, including a simulated parser crash.