Release validation source bytes after checks

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # Computational Efficiency Implementation Plan
 
-**Status:** Stages 1–5 complete; Stages 6–11 pending.
+**Status:** Stages 1–6 complete; Stages 7–11 pending.
 
 ## Purpose And Baseline
 
@@ -359,6 +359,22 @@ buffers after formatting, and duplicate-content files retain per-path findings.
 Record the tradeoff for explicit repeated raw reads. Update validation mechanics
 with the new ownership and reuse choices.
 
+**Completion:** Complete. Regular-file reads now return independent bytes and
+are not retained by `CandidateTree`; repeated explicit reads therefore transfer
+the blob again. The tree caches owned symlink-target strings by object ID, and
+explicit symlink reads still return independent byte slices. Go formatting
+caches only successful formatted/unformatted outcomes by object ID, checks
+cancellation per path, and reports every unformatted path even when contents
+repeat. Validation tests and the formatting/Markdown destination benchmarks
+passed. On the same Go 1.26.8, Git 2.53.0, Linux x86_64 Intel Core i5-7260U
+setup, three repetitions measured unique-file formatting at 75.0–75.9 ms loose
+and 37.9–42.5 ms packed, repeated-ID formatting at 1.97–2.17 ms, and the
+Markdown workload at 16.3–17.0 ms. Formatting used about 2.89 MB/op for unique
+files and 121 KB/op for repeated IDs. The retained-memory observation was
+129,496 bytes with the candidate and Markdown cache alive, compared with
+1,385,040–1,385,616 bytes in the baseline fixture. This retains Markdown parser
+data by path until Stage 7; it is a workload-specific heap observation.
+
 ## Stage 7: Reuse Owned Markdown And Module Results
 
 **Owners:** [markdown.go](../../internal/validation/markdown.go),