feat(secrets): add resolving-secrets skill and update lunatask references

Amolith created

Add new resolving-secrets skill for wrapping shell commands with opx to
resolve secret references in environment variables. Update lunatask CLI
references to mention trying lune directly first before falling back to
the resolving-secrets skill.

Assisted-by: Kimi K2 Thinking via Crush <crush@charm.land>

Change summary

skills/creating-tasks-through-lunatask/references/cli.md |  2 +
skills/resolving-secrets/SKILL.md                        | 19 ++++++++++
skills/resolving-secrets/references/installing-opx.md    |  1 
skills/resuming-work-through-lunatask/references/cli.md  |  2 +
4 files changed, 24 insertions(+)

Detailed changes

skills/creating-tasks-through-lunatask/references/cli.md πŸ”—

@@ -1,5 +1,7 @@
 When MCP tools are unavailable, use `lune` CLI. Destructive actions are interactive unless supplied `--force`.
 
+**Try `lune` directly first**β€”it integrates with the system keyring. Only fall back to the `resolving-secrets` skill if the user isn't using keyring-based credential storage.
+
 ## Creating tasks
 
 ```bash

skills/resolving-secrets/SKILL.md πŸ”—

@@ -0,0 +1,19 @@
+---
+name: resolving-secrets
+description: Wraps shell commands to resolve secret references in environment variables to their actual values. Always use when invoking synu, crush, gh, hut, etc. Ask whether to use if an invocation fails due to missing credentials.
+compatibility: Requires `fish` shell and `opx` Fish function
+license: AGPL-3.0-or-later
+metadata:
+  author: Amolith <amolith@secluded.site>
+---
+
+Prefix commands with `fish -c "opx ..."`.
+
+```bash
+fish -c "opx synu claude -p 'prompt'"
+fish -c "opx hut todo ticket show -t '~singpolyma/soprani.ca' 465"
+fish -c "opx gh issue view 123"
+fish -c "opx crush"
+```
+
+Refer to [installing-opx.md](references/installing-opx.md) if it's unavailable.

skills/resuming-work-through-lunatask/references/cli.md πŸ”—

@@ -1,5 +1,7 @@
 When MCP tools are unavailable, use `lune` CLI. Destructive actions are interactive unless supplied `--force`.
 
+**Try `lune` directly first**β€”it integrates with the system keyring. Only fall back to the `resolving-secrets` skill if the user isn't using keyring-based credential storage.
+
 ## Showing task details
 
 ```bash