[anneal] Remove v1 Lake cache symlinks

Findings: lake --old helps but is not enough if archive inputs have fresh mtimes, and without a root manifest Lake reconfigures path dependencies and writes locks into read-only package config trees; Lake manifest path entries can be relative to the generated workspace. In response, v1 generated workspaces now require Aeneas directly from the installed archive, write a locked relative lake-manifest.json, stop copying Aeneas/packages and symlinking .lake/build, and the archive build primes config caches, rewrites upstream trace prefixes, and makes Lake inputs older than prebuilt artifacts.

gherrit-pr-id: Gf5g4ujwxwoivi2uce2w3zt2hemew6jfi

Author: mdittmer

anneal/Cargo.lock

@@ -68,6 +68,7 @@ console = "0.16.3"
 exocrate = { path = "../exocrate" }
 sha2 = "0.10"
 fs2 = "0.4"
+pathdiff = "0.2.3"
 toml = "0.8"
 tempfile = "3.27.0"