fix repl-block, check-tangle, commands: READMEs, exit codes, path resolution

repl-block:
- Listing mode exits 0, not 1 (listing is not an error)
- Dead lines parameter removed from find_by_function
- Block listing goes to stderr (not stdout) so piped use works
- Added README.org

check-tangle:
- Fixed tangle tool resolution: prefer local projects/tangle-tool/tangle
- Fixed path resolution for relative and absolute tangle paths
- Removed 2>/dev/null suppression so tangle errors are visible
- Added README.org

Commands:
- Rewrote all three .opencode/commands/*.md with proper prompts

.opencode/commands/check-parens.md

@@ -3,6 +3,9 @@ description: Check paren balance in lisp blocks of .org files
 ---
 
 Run `projects/check-parens/check-parens` on the given .org files to verify all
-`#+begin_src lisp` blocks have balanced parentheses.
+`#+begin_src lisp` blocks have balanced parentheses. Uses SBCL's reader for
+100% accuracy — no false positives from string literals or character literals.
+
+Exit 0 if all blocks balanced, 1 if any issues found.
 
 Usage: /check-parens <file.org> [<file.org> ...]

.opencode/commands/check-tangle.md

@@ -3,6 +3,13 @@ description: Tangle an org file and compile the result
 ---
 
 Tangle an .org file to .lisp then compile with SBCL. Reports the first
-compile error. Exit 0 = clean, exit 1 = compilation error.
+compile error with line numbers. Exit 0 = clean compile, exit 1 = error.
+
+Prepares code for commit by ensuring the tangled .lisp file is syntactically
+valid. Catches missing symbols, undefined functions, and type errors before
+they reach the running daemon.
 
 Usage: /check-tangle <file.org>
+
+Example:
+  /check-tangle projects/passepartout/org/channel-tui-main.org

.opencode/commands/repl-block.md

@@ -2,12 +2,16 @@
 description: Send a lisp block from an org file to the REPL
 ---
 
-Extract a `#+begin_src lisp` block from an .org file and send it to the
-running daemon REPL.
+Extract a `#+begin_src lisp` block from an .org file and pipe it to the
+running daemon REPL. Identify the block by function name or index.
+
+The `--package` flag wraps the block in `(in-package ...)` so it evaluates
+in the right namespace — essential when the block references symbols from
+a specific package without the package prefix.
 
 Usage: /repl-block <file.org> --function <name>
-       /repl-block <file.org> --block <number>
        /repl-block <file.org> --function <name> --package <pkg>
+       /repl-block <file.org> --block <number>
 
-The --package flag wraps the block in an (in-package ...) form.
-Use --block to identify by 1-based index, --function to find by defun name.
+Example:
+  /repl-block projects/passepartout/org/channel-tui-view.org --function view-status --package :passepartout.channel-tui