Transient Anna's failures are recorded as definitive: the only book-capable source is never retried

[roomi-fields]

What happens

already_tried() treats failed as a definitive verdict, so a source that once returned failed is skipped for that ref forever. But two of Anna's most common outcomes are explicitly transient:

• annas_headful_optin | failed | budget_exhausted_retry_later — the reason literally says retry later
• annas_archive_optin | failed | md5_found_but_no_dl — the fingerprint was found, only the download slot was rationed

Once either is recorded, both Anna's routes report skipped_already_tried on every later pass. run --retry-exhausted lifts the ref-level cascade_exhausted_needs_manual lock but not this source-level memory, so the ref is re-planned and then skips the only sources that could serve it.

Observed on 0.4.0

Three books re-run today with run --ref … --retry-exhausted, full 16-source cascade:

manual_oa_url        no_source   no_oa_url_in_frontmatter
crossref_oa          no_source   no_doi
arxiv                no_source   no_arxiv_id
openalex_oa          no_source   no_oa_url
unpaywall            no_source   no_doi
hal                  no_source   hal_no_match_or_no_file
core                 no_source   no_core_match
publisher_doi        no_source   no_doi
archive_org          no_source   ia_no_match_above_threshold
publisher_headful    no_source   no_doi_and_no_manual_url
scihub_optin         no_source   no_doi
annas_archive_optin  skipped_already_tried
libgen_optin         no_source   no_doi
annas_scidb_optin    no_source   no_doi
annas_headful_optin  skipped_already_tried
websearch            no_source   websearch_already_queued

Result: planned=3 done=0 blocked=3. The browser starts fine and the shared session works (profile created, Chromium alive throughout) — it is simply never asked to do anything.

Second observation, same run: the new routes are DOI-gated

publisher_doi, publisher_headful, libgen_optin and annas_scidb_optin all return no_doi on books. libgen.py searches Libgen by DOI only, though Libgen's main strength is monographs — a title+author search would make it the book route the release notes describe. As it stands, for a reference without a DOI (any book), 0.4.0 adds no reachable source.

Suggested fix

• Split the verdict: keep failed definitive, add a transient verdict (or let already_tried() re-open attempts whose reason matches retry_later / no_dl / no_slot).
• Have --retry-exhausted also clear source-level transient attempts, not just the ref lock.
• Give libgen_optin a title+author search path when no DOI is present.

Environment

paper-trail 0.4.0, Debian container, xvfb-run, RESEARCH_ENABLE_SHADOW_LIBS=1, RESEARCH_BROWSER_PROFILE on a mounted volume, RESEARCH_MIN_BOOK_PAGES=30.