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/provenance_shell.h

@@ -0,0 +1,71 @@
+#pragma once
+// provenance_shell — the REAPER-facing reads Milestone 10 needs, in one place.
+//
+// The PURE provenance module (provenance.h) owns the fingerprint encoding, the
+// recipe model, the FX-identity fold, and the parent-detection DECISION — all over
+// plain strings/values. This shell gathers those strings/values FROM REAPER:
+//   * the in-scope FX-chain identity of a source track (name/GUID/enabled rows),
+//   * the media-file paths of a resolved capture's source items,
+//   * the active book's bank samples resolved to absolute file paths,
+//   * a canonical track-GUID string back to a live MediaTrack*.
+//
+// REAPER-facing: the .cpp includes reaper_plugin_functions.h WITHOUT
+// REAPERAPI_IMPLEMENT (main.cpp owns the API pointers; here they are extern —
+// CLAUDE.md §contract). MediaTrack is forward-declared so this header stays
+// SDK-lite. It depends on the pure provenance module (FxIdentityEntry / recipe /
+// BankFileRef) and bank_book (to enumerate the active book's samples).
+
+#include <optional>
+#include <string>
+#include <vector>
+
+#include "provenance.h"
+
+class MediaTrack;
+
+namespace reasampler {
+
+class BankBook;
+
+// The in-scope FX-chain identity of a source track, folded to the pure
+// provenance string. For TRACK scope this is the track's own FX chain; for ITEM
+// scope the take/item FX are the in-scope chain — but item/take FX are not
+// enumerable via the TrackFX_* family, so an item-scope capture folds an EMPTY
+// chain identity (the drift signal then keys on scope + range only, which is
+// honest: we do not claim to fingerprint take FX we cannot read). TRACK scope reads
+// TrackFX_GetCount / GetFXName / GetFXGUID / GetEnabled in chain order.
+std::string fxChainIdentityForTrack(MediaTrack* tr);
+
+// Reads the media-file path of every SELECTED media item's active take source
+// (GetMediaItemTake_Source -> GetMediaSourceFileName), normalized to forward-slash.
+// Unresolvable items (no take / no source / empty name) are omitted — never an
+// empty string in the result, so detectParent's "not in bank" branch is honest.
+// The active-project selection is read directly (mirrors main.cpp's collectors).
+// This is the ITEM-scope source set (the user selected the items being resampled).
+std::vector<std::string> selectedItemSourceFiles();
+
+// The TRACK-scope source set: the media-file paths of the items ON `tracks` that
+// OVERLAP the capture range [startSeconds, endSeconds). For a track capture the user
+// selects the track, not the item, so the "what audio is being captured" set is the
+// range-overlapping items on the source tracks. Same normalize + omit-unresolvable
+// contract as selectedItemSourceFiles. An item overlaps iff its [pos, pos+len)
+// intersects the range with positive overlap (a zero-length touch does not count).
+std::vector<std::string> trackItemSourceFiles(const std::vector<MediaTrack*>& tracks,
+                                              double startSeconds, double endSeconds);
+
+// Enumerates the ACTIVE book's samples across every bank (pool + named) as pure
+// BankFileRefs — each sample id paired with its file resolved to a normalized
+// ABSOLUTE path against `projectDir` (resolveBankFile + normalizeSlashes). A sample
+// whose path cannot be resolved (empty projectDir / empty relativePath) is emitted
+// with an empty absolutePath, which detectParent never matches. `projectDir` is the
+// current .rpp parent (the shell resolves it; empty -> all refs unresolved).
+std::vector<BankFileRef> bankFileRefs(const BankBook& book, const std::string& projectDir);
+
+// Resolves a canonical track-GUID string (guidString form) to a live MediaTrack*
+// in the active project by scanning tracks and comparing guidString(tr). Returns
+// nullptr when no live track carries that GUID (the source track was deleted since
+// capture — a re-capture failure mode the caller reports). The master track is not
+// scanned (it has no membership GUID and is never a capture source).
+MediaTrack* trackByGuid(const std::string& guid);
+
+}  // namespace reasampler