M10: provenance populate + re-capture from source (bank-only)

Pure provenance core (recipe fingerprint, FX-chain identity, parent
detection) + shell reads; capture stamps provenance on resample-from-sample;
re-capture regenerates a provenanced sample from its source, never touching
the timeline. Adds BankIndex/BankBook in-place update. CTest-covered.

src/bank_book.h

@@ -197,6 +197,16 @@ public:
                               const std::string& fromBankId,
                               RemoveScope scope = RemoveScope::ThisBank);
 
+    // Refreshes a sample IN PLACE wherever it lives in the book (M10 re-capture):
+    // finds the bank holding `sampleId` and replaces its entry with `updated`
+    // (order-preserving, no dedup — see BankIndex::updateInPlace). Scans banks in
+    // ordinal order and updates the FIRST holder (a sample id is unique within a
+    // bank; the same id living in two banks via copy would update the earliest, which
+    // is acceptable — re-capture operates on the panel's focused single selection).
+    // Returns false (no mutation) if no bank holds the id or the replacement's path
+    // is absolute. Index-only and non-destructive to the timeline.
+    bool updateSampleInPlace(const std::string& sampleId, const Sample& updated);
+
     // Reference-count query backing the confirm-on-last-reference guardrail: does any
     // bank OTHER than `exceptBankId` still hold an entry whose contentHash == `hash`?
     //