docs(journal): make project attribution mandatory effort, tag conditional output

[KadenMc]

What

Reworks the journal-update tagging rule in journal/update-directions. Previously every Log entry had to carry a #projects/<slug> prefix, with a fake #projects/unknown slug as the fallback for unattributable activity. That placeholder masquerades as a real project and pollutes the #projects/* namespace.

Why

A single "MUST tag every entry" rule conflated two different jobs. This splits them:

• Attribution stays mandatory effort — every entry must still attempt resolution via project_list + aliases.
• The tag is conditional output — emitted only on a genuine match, using the canonical registry slug (not an alias). After an attempted-and-failed match the entry is left untagged; no placeholder slug.
• Omissions are surfaced at approval ("N entries I couldn't attribute: ...") so they stay visible and auditable, never silent.

This preserves the anti-laziness pressure of the old rule (the agent still has to do the attribution work) while killing the bogus-slug failure mode.

Also fixes the worked example to use the canonical #projects/ecg-inquiry instead of the electricrag alias.

Scope

Knowledge-store edit to journal/update-directions only. No code change — journal.py never enforced the tag; the rule lives entirely as directions prose. docs_validate passes clean (434 units, all 14 checks).

Verification

A blind behavioral test (a naive agent given only the new directions, with no hint of the expected outcome) confirmed the intended behavior end to end:

• attributed entries tagged with the canonical slug (electricrag → #projects/ecg-inquiry),
• a genuine non-project life event (an evening meditation sit) left untagged and flagged at approval, rather than stamped #projects/unknown.