functionality for charsets added

README.md

@@ -18,6 +18,7 @@ himi                   # generate → clipboard
 himi -o                # generate → clipboard + stdout
 himi -o secure         # use 'secure' template → clipboard + stdout
 himi -n 5 -o easy      # generate 5 'easy' secrets → clipboard + stdout
+himi -q                # stdout only, skip clipboard (or HIMI_NO_CLIP=1)
 himi test '{word}-{num:2}'      # test a custom template
 ```
 
@@ -93,9 +94,29 @@ TEMPLATES=(
 | `{safe:N}` | N chars, ultra-safe (no ambiguous chars) | ~4.6 bits/char |
 | `{num:N}` | N digits | ~3.3 bits/char |
 | `{special:N}` | N from `!?@#%~=+` | ~3.0 bits/char |
+| `{NAME:N-M}` | N to M chars from charset NAME | log2(Σ size^L) |
 
 \* Word entropy depends on pool size. Values shown assume all built-in lists enabled (~14k words, ~13.8 bits/word).
 
+### Custom charsets
+
+Add `"name|characters"` entries to `CHARSETS` in the config, then use `{name:N}` or `{name:N-M}` in any template:
+
+```bash
+CHARSETS=(
+  "hex|0123456789abcdef"
+  "b58|123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
+)
+```
+
+Names must match `[a-z][a-z0-9_]*` and override the built-in four (alpha, safe, num, special). Avoid duplicate characters; himi warns if it sees them, since they skew the distribution and overstate entropy.
+
+Range tokens pick the length weighted by `size^L`, so every possible output is equally likely. `{num:1-2}` covers 0-99 plus 0-9 (110 outcomes, ~6.8 bits), not a 50/50 coin flip on length, which would tank min-entropy.
+
+### Integrity checks
+
+`himi rebuild` records a SHA-256 of the pool; generation refuses if `pool.txt` was modified outside of himi (accidental edits, sync corruption, casual tampering). himi also refuses to source a config file that isn't owned by you or is group/world-writable, since the config is executed shell. Neither check stops an attacker who can already write to your home directory (nothing can), but they catch everything short of that.
+
 ## Entropy rules of thumb
 
 | Bits | Strength | Use case |