Rename spec files to Torah-faithful names per parshah

Each spec corresponds to a parshah of Shemot. The earlier names
were generic English (materials, operations, construction,
economic_model). Torah names them precisely:

- Shemot 25:2 — terumah (תרומה, root רום, "what is lifted")
- Shemot 27:20 — tamid (תמיד, "continual" — the lamp that never goes out)
- Shemot 35:1 — vayakhel (קהל, "assembled" — community-formed building)
- Shemot 38:21 — pekudei (פקד, "accounted" — every material counted)

Renames:
  shorashim_materials.md       → shorashim_terumah.md
  shorashim_operations.md      → shorashim_tamid.md
  shorashim_construction.md    → shorashim_vayakhel.md
  shorashim_economic_model.md  → shorashim_pekudei.md

Updated cross-references in:
- README.md (parshah table + repo tree, also fixed stale tree
  showing src/ and transcripts/ that no longer exist)
- AGENTS.md
- BUILD_KORBAN.md
- specs/shorashim_terumah.md (internal Document Registry)

Generic English is silver. Torah's words are gold (Mishlei 25:11).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

BUILD_KORBAN.md

@@ -12,7 +12,7 @@ Read these files in this order. Do not summarize from memory. Read fresh.
 
 1. `specs/structure_not_content.md` — **Read this first.** This changes what the build means.
 2. `specs/shorashim_architecture.md` §3.5 (Korban Processor)
-3. `specs/shorashim_construction.md` §1.4 (Python dependencies), §3.4 (external model API contracts)
+3. `specs/shorashim_vayakhel.md` §1.4 (Python dependencies), §3.4 (external model API contracts)
 4. `specs/broken_tablets/README.md` — see where the calf was
 5. This file